as in treacherous
formal
causing harm in a way that is gradual or not easily noticed
Most people with this insidious disease have no idea that they are infected. an insidious enemy
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Recent Examples of insidious
And now the sort of very insidious paradox here is that when, not if, when Black representation is halved in the next year or two, in the next couple cycles, that will not be able to be used as a rationale for fixing that problem.
—
Hanna Rosin, The Atlantic, 14 May 2026
Underlying such obvious acts of aggression lies an insidious tendency for transnational repression to flow from despots into democracies, oppressing lawyers of all nationalities in the process.
—Irwin Cotler, Time, 8 May 2026
Among Vought’s litany of insidious secrets is the fact that its origins are tied to the Nazi Party and the Holocaust.
—Encyclopedia Britannica, 5 May 2026
That is exactly what this film cleverly does — pinpoints the insidious nature of far-right movements and the creeping rhetoric that has polluted our society.
—Alex Ritman, Variety, 30 Apr. 2026
See All Example Sentences for insidious
Hanna Rosin, The Atlantic, 14 May 2026
Underlying such obvious acts of aggression lies an insidious tendency for transnational repression to flow from despots into democracies, oppressing lawyers of all nationalities in the process.
—Irwin Cotler, Time, 8 May 2026
Among Vought’s litany of insidious secrets is the fact that its origins are tied to the Nazi Party and the Holocaust.
—Encyclopedia Britannica, 5 May 2026
That is exactly what this film cleverly does — pinpoints the insidious nature of far-right movements and the creeping rhetoric that has polluted our society.
—Alex Ritman, Variety, 30 Apr. 2026
See All Example Sentences for insidious
Recent Examples of Synonyms for insidious
Adjective
-
Installing his defensive ideals will be key to getting the Pels back to being competitive consistently in the treacherous Western Conference.—
William Guillory,
New York Times,
27 May 2026
-
Many make long commutes over treacherous mountain roads to get to their workplace.—
Ernesto Sagás,
The Conversation,
26 May 2026
Adjective
-
The collection is highly versatile, offering both subtle nods to the sport and head-to-toe outfits, all created in a patriotic color palette of red, white and a variety of blues.—
Kelsey Legg,
ABC News,
3 June 2026
-
The actress, also known for Todd Haynes' film May December, later comments on that subtle addition in a May 2026 interview.—
Entertainment Weekly,
Entertainment Weekly,
3 June 2026
Adjective
-
Today, rumors circulating on social media in the DRC include false claims that Ebola is not real, that humanitarian workers are descending on the area solely for their own profit and that aid groups are withholding the best care available.—
Gabrielle Emanuel,
NPR,
29 May 2026
-
In January, Roberts pleaded guilty to making a false statement for employment and one count of unlawfully possessing a firearm while being in the country illegally.—
Corky Siemaszko,
NBC news,
29 May 2026
Adjective
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This isn’t an easy history to tell since obfuscation, confusion, and deceptive hype are its central themes.—
Jonathan Odden,
Artforum,
2 June 2026
-
Owens also challenged the ballot title and summary as deceptive.—
Jack Harvel
June 2,
Kansas City Star,
2 June 2026
Adjective
-
This is perhaps the most perfidious practice of this sort of politics.—
David M. Drucker,
Twin Cities,
3 June 2026
-
Pakistan was a perfidious ‘ally’ in Afghanistan, backing the Taliban while pretending to be our friends.—
Efrat Lachter,
FOXNews.com,
18 Apr. 2026
Adjective
-
But according to an opinion from the Florida Attorney General’s Office, the city’s position is incorrect.—
Aaron Leibowitz,
Miami Herald,
2 June 2026
-
Some readers may disagree with our analysis, and of course there are many decisions that the KMI panel deemed correct or incorrect that fans from all teams will dispute.—
Graham Scott,
New York Times,
2 June 2026
Adjective
-
Wirskye then asked who was wrong that day.—
Dawn White,
CBS News,
7 June 2026
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Lauren McCormick, a spokeswoman for travel insurance provider Squaremouth, says your phone is the most efficient tool for protecting your travel investment if things go wrong.—
Christopher Elliott,
Forbes.com,
6 June 2026
Cite this Entry
“Insidious.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/insidious. Accessed 7 Jun. 2026.
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